过偏晶Cu-40wt%Pb合金的均质化凝固

Homogeneous Solidification of Cu-40wt%Pb Hypermonotectic Alloy

利用电磁模拟微重力和深过冷的方法,对过偏晶 Cu-40wt％Pb 合金的凝固组织进行了研究。比较了通过上述方法得到的凝固组织与常规凝固条件下的凝固组织,结果表明:采用电磁模拟微重力方法的凝固过程中没有出现 Stocks 沉积效应,得到的凝固组织中 Pb 颗粒均匀地分布在 Cu 基体上;而采用深过冷方法获得的凝固组织中,过冷度在40～80K 区间内 Pb 以纤维和颗粒的形式均匀分布在 Cu 基体上,并随过冷度的增加其分布的不均匀性亦增加。当过冷度超过80K时,第二相的重力沉积明显增加,并随过冷度的增加凝固组织中出现了与常规条件凝固一样的分层现象。

The microstructure of Cu-40wt%Pb hypermonotectic alloy are obtained with the techniques ofelectro-magnetic simulating microgravity and high undercooling,and a comparison with the microstructures under thecondition of general solidification is carried out.It is found that the S(Pb)particles disperse in S(Cu)matrix in the mi-crostructure achieved under the condition of electro-magntic simulating microgravity,in which gravity segregationdoes not occurs;In the microstructure with the undercooling method,S(Pb)disperse evenly in the shape of particlesand fibers within the undercooling range of 40K～80K and the distribution of S(Pb)become more non-homogeneouswith the increase of undercooling.However,when undercooling exceeds 80K,the gravity segregation of the the secondphase plays an important role,and there exists the separated structure similar to that solidified under the general con-dition with the increase of undercooling.